This application is based upon and claims priority from Japanese patent application Nos. Hei 10-135361, filed on May 18, 1998, and Hei 10-370324, filed on Dec. 25, 1998, and Hei 11-40289, filed on Feb. 18, 1999.
1. Field of the Invention
The present invention relates to an air conditioner for a vehicle in which the mounting performance of the air conditioner in an instrument panel at the front in a passenger compartment is improved.
2. Description of Prior Art
Conventionally, in an air conditioner for a vehicle, when an air conditioning unit is arranged in the vicinity of an instrument panel at the front in a passenger compartment, such a semicentral installation layout is put to practical use that the air conditioning unit incorporating an evaporator for cooling, a heater core for heating, a blow mode changing mechanism, and the like is arranged at substantially the central portion of the instrument panel in a vehicle right-and-left direction, and an air blower for sending air to the air conditioning unit is offset arranged at a side of the air conditioning unit and at a passenger seat side.
Besides, a complete central installation layout in which an air blower is arranged at the vehicle front side of the air conditioning unit is also partially put to practical use.
In both of the conventional semicentral installation layout and the complete central installation layout in a mounted state on a vehicle, generally, a cool air passage bypassing a heater core (heat exchanger for heating) is arranged over the heater core, and in both a face mode and a foot mode, a common cool air passage and a common air mixing chamber are used to adjust blow air temperature by adjusting the mixture of cooled air and warmed air.
In order to increase the amount of cooled air at the maximum cooling mode, the shape of the cool air passage and the air mixing chamber of the air conditioning unit is generally designed to give priority to reducing the pressure loss in the face mode. Thus, in many cases, an air passage for the foot mode has a bent shape, so that the pressure loss is increased during the foot mode.
The present invention is made in light of the foregoing problem, and it is an object of the present invention to provide an air conditioner for a vehicle in which both the reduction of pressure loss in the foot mode and the improvement of a mounting performance on a vehicle are achieved.
According to a first aspect of the present invention, an air conditioner has a face cool air passage and a foot cool air passage formed separately from the face cool air passage. The face cool air passage is formed to bypass a heating heat exchanger and to introduce cooled air to a face opening portion. The foot cool air passage is formed to bypass the heating heat exchanger and to introduce cooled air to a foot opening portion.
The foot cool air passage is located at a side of the heating heat exchanger in a vehicle right-and-left direction. Cooled air from the foot cool air passage and warmed air heated by the heating heat exchanger are mixed at an inlet of the foot opening portion.
According to the first aspect of the present invention, the temperature of air blown from the face opening portion and the foot opening portion is excellently controlled by adjusting the ratio of amounts of cooled air and warmed air.
Further, since the foot cool air passage is independently formed from the face cool air passage, and cooled air and warmed air are mixed at the inlet side of the foot opening portion, the warm air passage at a downstream side of the heating heat exchanger is formed to have a shape that the passage has few bends and reaches the inlet side of the foot opening portion in a short distance without being restricted by the shape of the face cool air passage. Accordingly, pressure loss at the foot mode is reduced, and the amount of air at the foot mode is increased.
Further, not only the face cool air passage and the foot cool air passage are formed independently, but the foot cool air passage is also arranged at the side of the heating heat exchanger in the vehicle right-and-left direction. Therefore, the foot cool air passage can be arranged at positions shifted from the face cool air passage in the vehicle right-and-left direction. Thus, the increase of the size of the entire case of the air conditioning unit in a vehicle top-and-bottom direction is prevented.
Furthermore, since the warm air passage at the downstream side of the heating heat exchanger can be directly guided to the inlet side of the foot opening portion without being bent in the vehicle top-and-bottom direction, the size in a vehicle front-and-rear direction is also reduced. Accordingly, the mounting performance of the air conditioning unit on the central portion of the vehicle is improved.
According to a second aspect of the present invention, the face cool air passage is located over an upper portion of the heating heat exchanger, and the foot cool air passage is bent downwardly after it passes through an upper side of the side of the heating heat exchanger.
Accordingly, since both the face cool air passage and the foot cool air passage are positioned at the upper side of the heating heat exchanger in the vehicle top-and-bottom direction, the amount of cooled air passing through the face cool air passage and the foot cool air passage can be adjusted by a common temperature adjusting means, so that the structure is simplified.
According to a third aspect of the present invention, the foot opening portions are arranged at both sides of the case in the vehicle right-and-left direction, and the foot cool air passages are arranged at both sides of the heating heat exchanger in the vehicle right-and-left direction correspondingly to the respective foot opening portions.
Accordingly, cooled air is directly introduced to the inlet side of the foot opening portions at both the sides in the right-and-left direction through the foot cool air passages at both the left and right sides with a small bent angle.
According to a fourth aspect of the present invention, a width of the heating heat exchanger in the vehicle right-and-left direction is less than a width of the cooling heat exchanger in the vehicle right-and-left direction, and the foot cool air passage is arranged at the side of the heating heat exchanger in the vehicle right-and-left direction and within a range of the width of the cooling heat exchanger in the vehicle right-and-left direction.
Accordingly, the foot cool air passage is arranged while surplus spaces produced at the sides of the heating heat exchanger in the vehicle right-and-left direction are effectively used, so that the size of the entire case of the air conditioning unit is effectively decreased.
Furthermore, the width of the cooling heat exchanger in the vehicle right-and-left direction is greater than the width of the heating heat exchanger. Therefore, the size of the cooling heat exchanger in the top-and-bottom direction is reduced, and the size of the entire case of the air conditioning unit in the top-and-bottom direction is reduced.
Further, by the enlargement of the width size of the cooling heat exchanger in the vehicle right-and-left direction, cooled air is widely blown toward the upper half of the passenger at the face mode (at the time of cooling) by effectively using the oblong shape of the cooling heat exchanger. Thus, a feeling of cooling is improved by increasing a sense of cooled air flow to the passenger, and at the same time, bends of cooled air are reduced, and the reduction of pressure loss at the face mode is achieved.
According to a fifth aspect of the present invention, the width W0 of the heating heat exchanger in the vehicle right-and-left direction is set to satisfy the following relation with respect to the width W of the cooling heat exchanger in the vehicle right-and-left direction:
(0.6xc3x97W)xe2x89xa6W0xe2x89xa6(0.8xc3x97W)
Accordingly, when the foot cool air passage is arranged at the side of the heating heat exchanger in the vehicle right-and-left direction and within the range of the width W of the cooling heat exchanger in the vehicle right-and-left direction, by making W0 not higher than 0.8xc3x97W, the width of the foot cool air passage is sufficiently secured and the amount of cooled air necessary for control of foot blow temperature is secured, so that the controllability of the foot blow temperature is improved. Moreover, by making W0 not lower than 0.6xc3x97W, a required heat transfer area of the heating heat exchanger is secured and necessary heating capacity of the heating heat exchanger is secured.
According to a sixth aspect of the present invention, the air conditioner has a defroster opening portion for blowing the air with a temperature adjusted by the temperature adjusting means toward a windshield, and the cooling heat exchanger has a width in the vehicle right-and-left direction comparable to the width of the case, and each of a width of the defroster opening portion and a width of the face opening portion in the vehicle right-and-left direction is smaller than the width of the cooling heat exchanger in the vehicle right-and-left direction.
Accordingly, the cooled air having passed the cooling heat exchanger is prevented from excessively flowing to the defroster opening portion and the face opening portion. As a result, the amount of flow of cooled air after the cooling heat exchanger through the foot cool air passage to the foot opening portion is increased, so that the excessive increase in temperature of foot blow air is prevented, and the temperature difference of upper and lower blow is suitably controlled, and the feeling of air conditioning is improved.
According to a seventh aspect of the present invention, the defroster opening portion is located at a vehicle front side relative to the face opening portion, and a defroster door for opening and closing the defroster opening portion is rotatably provided in the case, and the width of the defroster opening portion is smaller than the width of the cooling heat exchanger at a most vehicle front side of a rotary position of the defroster door.
Accordingly, the excessive inflow of cooled air to the defroster opening portion and the face opening portion is excellently suppressed while the rotating space of the defroster door is secured.
According to an eighth aspect of the present invention, the defroster opening portion and the face opening portion are arranged at a central portion of the case in the vehicle right-and-left direction, so that protruding amounts of the cooling heat exchanger to both of the defroster opening portion and the face opening portion in the vehicle right-and-left direction become comparable, and the blow-out temperature in the vehicle right-and-left direction is made uniform.
According to a ninth aspect of the present invention, the air conditioner includes a first foot door for controlling warmed air flow from the heating heat exchanger and a second foot door for controlling cooled air flow from the foot cool air passage. Further, the first foot door and the second foot door are linked together to control the air flow to the foot opening portion.
Accordingly, when the foot cool air passage is arranged at the side of the heating heat exchanger in the vehicle right-and-left direction, the cooled air flow and the warmed air flow are controlled by both of the first and the second foot doors to mix the cooled air and the warmed air at the downstream side of the doors.
According to a tenth aspect of the present invention, the first foot door is positioned at an upstream side of the inlet of the foot opening portion, so that the first foot door can be arranged outside of the warm air passage immediately after the heating heat exchanger, and airflow resistance of the warm air passage is reduced.